U.S. patent application number 11/823411 was filed with the patent office on 2007-11-08 for method and system for simultaneously displaying relationships of measurements of features associated with a medical image.
This patent application is currently assigned to Siemens Medical Solutions USA, Inc.. Invention is credited to Edward A. Gardner, Robert D. Kahn.
Application Number | 20070260143 11/823411 |
Document ID | / |
Family ID | 33517969 |
Filed Date | 2007-11-08 |
United States Patent
Application |
20070260143 |
Kind Code |
A1 |
Kahn; Robert D. ; et
al. |
November 8, 2007 |
Method and system for simultaneously displaying relationships of
measurements of features associated with a medical image
Abstract
The embodiments described herein relate to a method and system
for simultaneously displaying relationships of measurements of
features associated with a medical image. In one embodiment, a
plurality of measurements of features associated with a medical
image are provided. Each of the plurality of measurements
corresponds to a respective measurement type. Relationships are
created between the measurements and references specific to the
measurement types, and at least two of the created relationships
are simultaneously displayed in a graphical display format.
Examples using fetal growth data and time intensity curves are
disclosed. Other embodiments are provided, and each of the
embodiments described herein can be used alone or in combination
with one another.
Inventors: |
Kahn; Robert D.; (Saratoga,
CA) ; Gardner; Edward A.; (San Jose, CA) |
Correspondence
Address: |
SIEMENS CORPORATION;INTELLECTUAL PROPERTY DEPARTMENT
170 WOOD AVENUE SOUTH
ISELIN
NJ
08830
US
|
Assignee: |
Siemens Medical Solutions USA,
Inc.
|
Family ID: |
33517969 |
Appl. No.: |
11/823411 |
Filed: |
June 26, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10601413 |
Jun 23, 2003 |
7252638 |
|
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11823411 |
Jun 26, 2007 |
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Current U.S.
Class: |
600/458 |
Current CPC
Class: |
A61B 8/06 20130101; A61B
8/481 20130101; A61B 8/0866 20130101; A61B 5/415 20130101; A61B
8/463 20130101; A61B 5/416 20130101; A61B 5/1075 20130101 |
Class at
Publication: |
600/458 |
International
Class: |
A61B 8/14 20060101
A61B008/14 |
Claims
1-22. (canceled)
23. A medical diagnostic ultrasound imaging system comprising: a
beamformer; a transducer; a display device; and a processor in
communication with the beamformer, transducer, and display device,
wherein the processor is operative to: generate an ultrasound image
of a fetus undergoing ultrasound examination; generate a plurality
of fetal growth data based on measurements of anatomical components
shown in the medical diagnostic ultrasound image of the fetus; and
simultaneously display the plurality of fetal growth data in a
graphical display format on the display device.
24. The system of claim 23, wherein the processor is further
operative to normalize the plurality of fetal growth data and
display the plurality of fetal growth data in a single graph.
25. The system of claim 23, wherein the processor is further
operative to display the plurality of fetal growth data in separate
graphs.
26. The system of claim 23, wherein the graphical display format
shows the plurality of fetal growth data with respect to a mean and
a standard deviation.
27. The method of claim 23, wherein the graphical display format
shows, for at least some of the fetal growth data, a plurality of
data points acquired throughout pregnancy.
28. The system of claim 23, wherein the processor is further
operative to display a selected fetal growth data in an expanded
format.
29. The system of claim 23, wherein the plurality of fetal growth
data comprises at least one of the following: estimated fetal
weight, biparietal diameter, head circumference, abdominal
circumference, femur length, crown rump length, and
anterior-posterior trunk/thorax diameter. Claims 30-45. (canceled)
Description
BACKGROUND
[0001] Some of the objectives of an obstetric ultrasound
examination are to determine whether the growth of a fetus is
consistent with a best estimate of the fetus' age and to determine
whether the relative sizes of various anatomical components are in
correct proportion. To support these objectives, medical diagnostic
ultrasound imaging systems can display fetal growth data in the
form of "growth curves," which depict the expected size of a
component of fetal anatomy as a function of gestational age. FIG. 7
is an example of a conventional fetal growth curve showing
biparietal diameter (BPD) as a function of gestational age (GA)
over the course of a gestation. As shown in FIG. 7, the growth
curve comprises three distinct plotted curves: one representing the
mean or expected biparietal diameter for a given gestational age
(curve 1), and two other curves above and below the mean showing
the normal statistical variation to be found among healthy fetuses
(curves 2 and 3). The growth curve also shows a data point (X),
which is the biparietal diameter measurement acquired during an
ultrasound examination of a patient. A sonographer or physician
makes a determination regarding the status of the fetus by looking
at the growth curve to determine whether the measured anatomy lies
within a normal range.
[0002] Separate growth curves are generated for different types (or
"dimensions") of fetal growth data, and each of these growth curves
are examined to obtain a global picture of the normalcy of the
fetus'growth. Because growth curves only show a single dimension of
fetal growth data and current ultrasound systems and image review
systems only display a single growth curve at any given time, a
sonographer or physician must page through a sequence of growth
curves to diagnose the fetus'growth. This sequential analysis of
growth curves introduces a risk of a missed diagnosis since a key
growth curve can easily be overlooked. Similar problems can occur
with other measurements of features associated with a medical
image.
SUMMARY
[0003] The present invention is defined by the following claims,
and nothing in this section should be taken as a limitation on
those claims.
[0004] By way of introduction, the embodiments described herein
relate to a method and system for simultaneously displaying
relationships of measurements of features associated with a medical
image. In one embodiment, a plurality of measurements of features
associated with a medical image are provided. Each of the plurality
of measurements corresponds to a respective measurement type.
Relationships are created between the measurements and references
specific to the measurement types, and at least two of the created
relationships are simultaneously displayed in a graphical display
format. Examples using fetal growth data and time intensity curves
are disclosed. Other embodiments are provided, and each of the
embodiments described herein can be used alone or in combination
with one another.
[0005] The embodiments will now be described with reference to the
attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a flow chart of a method of an embodiment for
simultaneously displaying fetal growth data.
[0007] FIG. 2 is a block diagram of a medical diagnostic ultrasound
imaging system of an embodiment.
[0008] FIG. 3 is an illustration of a graphical display format of
an embodiment.
[0009] FIG. 4 is an illustration of a graphical display format of
another embodiment.
[0010] FIG. 5 is an illustration of a graphical display format of
another embodiment.
[0011] FIG. 6 is an illustration of a graphical display format of
another embodiment.
[0012] FIG. 7 is an illustration of a prior art growth curve.
DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS
Introduction
[0013] In general, the embodiments described below can be used to
simultaneously display relationships of measurements of features
associated with a medical image. In operation, a plurality of
measurements of features associated with a medical image are
provided. Each of the plurality of measurements corresponds to a
respective measurement type. For each of the plurality of
measurements, a relationship between the measurement and the
reference specific to its measurement type is created. Then, at
least two of the created relationships are simultaneously displayed
in a graphical display format.
[0014] A "measurement of a feature associated with a medical image"
can be any quantification of a physiological attribute that (a)
appears directly in a medical image (e.g., the diameter of a heart
chamber), (b) is a calculation derived from raw imaging data (e.g.,
a calculation of Resistance Index), or (c) is available through the
imaging system even though it is not data that is used to create a
medical image (e.g., heart-rate made available to the imaging
system via an EKG which plugs into the imaging system). The
following is a list of examples of various measurements of
features. This list is not comprehensive, and other measurements
can be made, such as those listed at
http://www.echobyweb.com/htm_level2_eng/formulas&calculations.htm.
[0015] Tumor diameter/area/volume. [0016] Various organ and organ
component diameters/areas/volumes. [0017] Blood flow velocity
through various significant vessels, for example, different sites
on the Carotid Arteries, the Pulmonary Vein, the Aorta, Hepatic
vessels, renal arteries, blood vessels in the legs. [0018]
Resistance index (RI) of blood flow through a vessel, where RI is
defined as |Vmax-Vmin|/max(|Vmax|, |Vmin|), where Vmax is the
systolic velocity and Vmin is the diastolic velocity measured
during a heart cycle. [0019] Time-Averaged-Velocity (TAV) of blood
flow through a vessel. This is the average flow velocity over a set
span of time. [0020] Pulsitility index (PI) of blood flow through a
vessel, where PI is defined as |Vmax-Vmin|/TAMx, where Vmax is the
systolic velocity, Vmin is the minium diastolic velocity, and TAMx
is the maximum velocity averaged over (at least) one cardiac cycle.
[0021] Ratio of blood velocity at systole and diastole. [0022]
Vascular Stenosis, which is the percent blockage of a blood vessel,
calculated from measurements of the vessel's outer diameter and
inner diameter, or alternatively the outer cross-sectional area and
inner cross-sectional area. [0023] Ejection Fraction, which is the
proportion of blood pumped out of the heart with each beat,
computed from measuring the percentage change in heart chamber
volumes between systole and diastole. [0024] Wash-in and wash-out
rates.
[0025] The measurements have normal ranges and ranges outside the
norm, which are indicative of some kind of pathology. Given that
there is an expected "normal" value (e.g., an average value found
among a healthy population) and an expected standard deviation away
from "normal" found among healthy persons, then any measurement can
be expressed in a unitless (normalized) way by using the following
equation: NormalizedMeasurementValue=(Measured Value-"Normal"
Value)/StandardDeviation. The NormalizedMeasurementValue is then
simply the number of standard deviations away from "Normal."
Because any measurement can be normalized in this way, regardless
of the measurement (whether it be a distance, a volume, a flow
velocity, etc), it is possible to meaningfully display diverse
measurements on the same x-y plot, where the vertical (y) axis is
the unitless measure of deviation (measured in standard deviations)
from normal and where the horizontal (x) axis is the plurality of
measurements of features associated with a medical image.
[0026] As discussed above, each of the plurality of measurements
corresponds to a respective measurement type, and each of the
plurality of measurements is associated with a reference specific
to its measurement type. If all of the measurements correspond to
the same measurement type, all of the measurements can be compared
to the same reference. Otherwise, each measurement can be
normalized to an appropriate reference specific to that measurement
type. Then, all the normalized measurements can be displayed
together to provide a meaningful comparison of the different
measurements relative to "normal." This makes it possible to
simultaneously display measurements of diverse nature, for example,
a heart rate (bpm), a flow velocity (m/s), and a wall thickness
(mm). Each of these is measured in different units, but they all
have expected ranges (e.g., an average value for healthy patients,
and a standard deviation to be found among healthy patients). By
normalizing each measurement relative to its expected range (e.g.,
how many standard deviations away from average is it?), all the
measurements are simultaneously displayable in a single plot.
Simultaneously displaying these relationships in a graphical
display format can be used to assist a user diagnose a healthy or
unhealthy condition. Various types of measurements can be
simultaneously displayed, and the choice of which types to
simultaneously display can be made by a user.
[0027] The following examples illustrate the embodiments described
above as applied to fetal growth data and time intensity curves. It
is important to note that these embodiments can be used in other
applications and that the following claims should not be limited to
fetal growth data or time intensity curves unless explicitly
recited therein.
Example Using Fetal Growth Data
[0028] One application of the general technique described above
relates to fetal growth data and will be described in conjunction
with the flow chart 100 of FIG. 1. As shown in FIG. 1, a medical
diagnostic ultrasound image of a fetus is generated with a medical
diagnostic ultrasound imaging system (act 110), such as the medical
diagnostic ultrasound imaging system 200 illustrated in FIG. 2. As
shown in FIG. 2, the ultrasound system 200 comprises a transducer
probe 205, a beamformer 210, a processor 220, a display device 230,
a storage device 240, and a user interface 250. Some or all of the
functionality described herein can be performed by the processor
220 running software (i.e., computer-readable program code) stored
in the storage device 240 or some other location not shown.
Alternatively, some or all of the functionality described herein
can be implemented purely with hardware (e.g., with the processor
220 alone and/or with other hardware component(s) not shown). The
hardware/software components can take any suitable form. Further,
the ultrasound system 200 can comprise additional components, which
are not shown in FIG. 2 for simplicity. For example, although only
a single processor 220 is shown in FIG. 2, it should be understood
that the ultrasound system 200 can comprise multiple processors and
that the functionality described herein can be performed by a
single processor or can be distributed among several
processors.
[0029] During an obstetrics ultrasound examination, a sonographer
contacts the transducer probe 205 with a patient, and the
ultrasound system 200 generates an ultrasound image of a fetus. In
general, the ultrasound system's processor 220 causes the
beamformer 210 to apply a voltage to the transducer 205 to cause it
to vibrate and emit an ultrasonic beam into the portion of the
patient's body in contact with the transducer 205. Ultrasonic
energy reflected from the patient's body impinges on the transducer
205, and the resulting voltages created by the transducer 205 are
received by the beamformer 210. The processor 220 processes the
sensed voltages to create an ultrasound image and displays the
image on the display device 230. In addition to being displayed on
the display device 230, a generated ultrasound image can also be
stored in digital form in the storage device 240 for later review.
Images can also be transferred to removable media (e.g., a
magneto-optical disk) or sent over a network (e.g., a local area
network in a hospital or the Internet).
[0030] Once the ultrasound image is displayed on the display device
230, the sonographer measures anatomical components shown in the
displayed ultrasound image using displayed measurement tools that
are manipulated with the user interface 250 (act 120). Based on the
measurements of the anatomical components, a plurality of fetal
growth data is generated (act 130). As used herein, the term "fetal
growth data" broadly refers to any data that is generated based on
a measurement of an anatomical component shown in a medical image
and that can be used to assess the growth of a fetus. As also used
herein, fetal growth data is "based on" a measurement when the
fetal growth data is the measurement itself or is the result of a
calculation using the measurement.
[0031] The following are some examples of fetal growth data. It
should be understood that the term "fetal growth data" as used in
the claims is not limited to the following examples and that other
forms of fetal growth data can be used. Information about these and
other fetal biometry measurements can be found at the following
sources, each of which is hereby incorporated by reference.
[0032] Hadlock, F. et. al., "Fetal Crown-Rump Length: Reevaluation
of Relation to Menstrual Age (5-18 weeks) with High-Resolution
Real-Time US," Radiology, vol. 182, no. 2, pages 501-505, February
1992;
[0033] Hadlock, F. et. al., "Estimating Fetal Age:
Computer-Assisted Analysis of Multiple Fetal Growth Parameters",
Radiology, vol 152, no. 2, pages 497-501, August 1984.
[0034] Chitty, L. et. al., "Charts of fetal size: 2. Head
measurements", British Journal of Obstetrics and Gynaecology, vol
101. pp 35-43, January 1994.
[0035] Chitty, et. al., "Charts of fetal size: 3. Abdominal
measurements", British Journal of Obstetrics and Gynaecology, vol.
101, pp. 1-7, February 1994.
[0036] Chitty, et. al., "Charts of fetal size: 4. Femur length",
British Journal of Obstetrics and Gynaecology, vol. 101, pp.
132-135, February 1994.
[0037] Hellman, L., et. al., "Growth and development of the human
fetus prior to the twentieth week of gestation", Am. J. Obst. &
Gynec., Volume 103, no. 6, pp. 789-800, Mar. 15, 1969.
[0038] Goldstein, I., et. al., "Cerebellar measurements with
ultrasonography in the evaluation of fetal growth and development",
Am. J. Obst & Gynec., Volumne 156, No. 5, pp 1065-1069, May
1987.
[0039] Hata, T. and R. Deter, "A Review of Fetal Organ Measurements
Obtained with Ultrasound: Normal Growth", J. Clin. Ultrasound
210:155-174, March/April 1992.
[0040] Jeanty, P. et. al., "Estimation of Gestational Age from
Measurements of Fetal Long Bones", Journal of Ultrasound in
Medicine, Volume 3, pp. 75-83, February 1984.
Biparietal Diameter (BPD)
[0041] The biparietal diameter is the transverse width of the head
measured between the two sides of the head. The biparietal diameter
can be used to calculate gestational age.
Head Circumference (HC)
[0042] The circumference of the fetus'head can be used to calculate
gestational age with a degree of accuracy that is slightly better
than that derived from the biparietal diameter.
Abdominal Circumference (AC)
[0043] Abdominal circumference is measured at the widest point in
the abdomen, through the liver at the level of the left portal vein
or stomach. Abdominal circumference is determined not only by
growing tissues (mainly liver) but also by nutrient storage such as
subcutaneous fat and liver glycogen. Serial measurements of the
abdominal circumference are useful in monitoring the growth of the
fetus.
Femur Length (FL)
[0044] The femur length measurement measures the longest bone in
the body and reflects the longitudinal growth of the fetus. Its
usefulness is similar to that of the biparietal diameter
measurement. Accuracy of gestational age from femur length
measurements is relatively independent of nutritional-growth
retarding processes.
Crown Rump Length (CRL)
[0045] The crown rump length measurement can be made between 7 to
13 weeks and gives an accurate estimation of the gestational age.
The crown rump length measurement is an early standard of reference
for fetal dating with ultrasound and is useful in the first
trimester of pregnancy
Estimated Fetal Weight (EFW)
[0046] Sonographic prediction algorithms use various combinations
of abdominal circumference (AC), femur length (FL), biparietal
diameter (BPD), and head circumference (HC), both singly and in
combination, to make fetal weight estimations.
Intracranial Organs
[0047] Ratio of the Cerebellum's Lateral Ventricular Width to the
Hemispheric Width (LVW/HW).
[0048] Cerebroatrial distance (CAD).
[0049] Ratio of the cerebroatrial distance (CAD) to hemispheric
width (HW).
[0050] Posterior Horn Width (PHW), measured from the medial wall to
the lateral wall of the posterior horn of the lateral
ventricle.
[0051] Cerebroposterior horn distance (CPHD), measured from the
medial wall to the lateral wall of the posterior horn of the
lateral ventricle.
[0052] Transverse cerebellar diameter (TCD).
Heart
[0053] Left ventricular transverse diameter (LVTD).
[0054] Right ventricular transverse diameter (RVTD).
[0055] Aortic diameter (AOD).
[0056] Pulmonary artery diameter (PAD).
Lung
[0057] Left lung circumference (LLC).
[0058] Right lung circumference (RLC).
[0059] Lung Area (LA) in a transverse section of the fetal thorax
containing the four-chamber view of the heart.
Thymus
[0060] Maximal Anterior-posterior diameter (APD) of the thymus,
measured in the midline at the sternum.
Liver
[0061] Liver Length (LL).
Spleen
[0062] Spleen Length (SL).
[0063] Spleen Width (SW).
[0064] Spleen Area (SA).
Pancreas
[0065] Length of fetal pancreas (FP-L).
Stomach
[0066] Longitudinal and anteroposterior diameters of the
stomach.
Kidney
[0067] Anteroposterior Diameter.
[0068] Transverse Diameter.
[0069] Length.
[0070] Circumference.
[0071] Area.
[0072] Volume.
Adrenal Gland
[0073] Fetal adrenal gland area (FAGA).
[0074] Fetal adrenal gland length (FAGL).
[0075] Fetal adrenal gland circumference (FAGC).
Intestine
[0076] Colon diameter (CD).
Bladder
[0077] Maximum bladder volume (MBV).
[0078] Fetal urine production rate (FUPR).
Misc.
[0079] Anterior-posterior trunk/thorax diameter (APTD).
[0080] Transverse trunk diameter (TTD).
[0081] Spine length (SL).
[0082] As mentioned in the background section above, different
dimensions of fetal growth data are typically displayed as separate
growth curves, with only one growth curve being displayed at a
given time. Because the sonographer must page through a sequence of
growth curves to obtain a global picture of the normalcy of the
fetus'growth, the sonographer can overlook an important growth
curve. To remove this risk, this embodiment simultaneously displays
the plurality of generated fetal growth data in a graphical format
(act 140). The plurality of fetal growth data is "simultaneously
displayed" when all of the plurality of fetal growth data is
presented at a given time to a user for viewing, even if a delay
prevents all of the fetal growth data from being initially
displayed exactly at the same instant. The term "simultaneously
display" is intended to distinguish from the sequential display of
fetal growth data, which occurs when a user pages through a
sequence of individual fetal growth curves to cause the display of
one fetal growth curve to be replaced by the display of a different
fetal growth curve. The plurality of fetal growth data can be
simultaneously displayed on a single display device or across
multiple display devices and can be presented in a single graph or
in multiple graphs. Further, while the phrase "graphical display
format" is intended to distinguish from a mere listing of numerical
data (e.g., a tabular chart of numerical values of fetal growth
data), no limit is intended on the form of the graphical format.
Additionally, it should be noted that the graphical display format
can include elements in addition to the various dimensions of fetal
growth data, such as an image or a chart of numbers.
[0083] Turning again to the drawings, FIG. 3 is an example of a
graphical display format of an embodiment that can be used to
simultaneously display fetal growth data. In the embodiment shown
in FIG. 3, six different dimensions of fetal growth data are
simultaneously displayed in a graphical format on a single page. In
this embodiment, each dimension is represented by a bar on a graph,
and abbreviations for each dimension of fetal growth data appear
along the bottom of the graph. Above each measurement name is a
bar, normalized so that the midpoint of the bar represents the
expected value (mean) of the physiology represented by the fetal
growth data, given the current estimate of the fetus'gestational
age, which is 30 weeks, 4 days in this example. The upper and lower
extents of each bar are normalized to represent the standard
deviations expected in the measurement of the physiology for a
normal fetus. Dots indicate measurements obtained during the
examination, and dots lying outside the normal range can be
color-coded for emphasis. If closer examination is required of a
particular dimension (e.g., BPD), the bar representing that
dimension can be selected using a user interface device and
expanded into a traditional growth curve plot.
[0084] In contrast to conventional display techniques in which each
dimension of fetal growth data is displayed on its own graph
separate from all other anatomical data, the display format of this
embodiment provides an improved mechanism for rapid determination
of the normalcy of the current fetal state by simultaneously
displaying several components of fetal growth data. In this
embodiment, values and standard deviations of several anatomic
measurements made during an examination are graphically displayed
side-by-side so that multiple dimensions of fetal growth data can
be quickly evaluated by a physician or sonographer. Because this
display format simultaneously displays multiple dimensions of fetal
growth data, a physician or sonographer can establish whether the
fetus is developing normally in a single glance. Providing a
multidimensional view of fetal growth data can significantly
decrease the likelihood that an important aspect of the fetal
physiology will be overlooked and, thus, reduce the possibility of
an inaccurate diagnosis or a misdiagnosis of fetal pathology. By
allowing all aspects of fetal development to be easily assessed by
examination of a single graph that presents all of the fetal growth
data in an easy-to-read format, the multidimensional display format
of this embodiment overcomes the disadvantages of existing growth
curve presentation techniques by providing a superior perspective
on all dimensions of fetal growth.
[0085] It should be noted that different graphical display formats
can be used to simultaneously display fetal growth data. For
example, as shown in FIG. 4, the graphical format of FIG. 3 can be
modified to allow the representation of fetal growth trends during
the gestation by including data from multiple examinations
throughout the gestation. In the graphical display format shown in
FIG. 4, each dimension of fetal growth data contains a set of
points representing data acquired throughout pregnancy, with the
right-most point in each bar representing the data collected at the
noted gestational age (30 weeks, 4 days).
[0086] FIG. 5 shows an alternate presentation of multidimensional
fetal growth data that includes results from multiple examinations
throughout gestation. In the graphical display format of FIG. 5,
biparietal diameter, head circumference, and abdominal
circumference are all plotted on the same graph. This graph
illustrates expected value (mean) and standard deviations for each
of the dimensions of fetal growth data versus gestational age. The
"dots" (squares, triangles, and circles) on the graph indicate
measurements obtained during the examination at various gestational
ages, and each of the dimensions of fetal growth data is normalized
with respect to the mean.
[0087] In the graphical display formats described above, multiple
dimensions of fetal growth data were plotted on the same graph
(i.e., different fetal growth data were overlapped onto the same
display area). In an alternate graphical display format (shown in
FIG. 6), multiple dimensions of fetal growth data are plotted on
separate graphs (i.e., on separate display areas), while still
being simultaneously displayed on a single display device 600. The
various dimensions of fetal growth data can be normalized with
respect to one another in this graphical display format.
[0088] In the embodiments described above, the fetal growth data
was simultaneously displayed on the ultrasound system that created
the image from which the fetal growth data was generated. In an
alternate embodiment, the fetal growth data is simultaneously
displayed on an image review system instead of on the ultrasound
system that created the image from which the fetal growth data was
generated. As used herein, the term "image review system" refers to
any device other than the ultrasound system that created the image
from which fetal growth data was generated that is capable of
simultaneously displaying a plurality of fetal growth data. An
image review system can be, for example, a general-purpose or
specialized computer, a personal digital assistant (PDA), or
another ultrasound system. The fetal growth data can be provided
from an ultrasound system to the image review system via removable
media (e.g., a magneto-optical disk), a network (e.g., a local area
network in a hospital or the Internet), a wireless transmission, or
any other suitable technique. In addition to simultaneously
displaying fetal growth data, the image review system can perform
other functions, such as displaying images, making measurements of
anatomical structures shown in the images, generating fetal growth
data based on the measurements, and creating medical reports.
[0089] Instead of simultaneously displaying fetal growth data,
these embodiments can be used to simultaneously display
non-obstetrics-based data (e.g., cardiology data). Data other than
that generated from measurements taken of anatomy shown in a
medical image can also be simultaneously displayed. The following
is an example using time intensity curves.
Example Using Time Intensity Curves (TIC)
[0090] Another application of the general technique described above
relates to time intensity curves (TIC) for cardiac contrast. TIC
curves provide a way of determining how well heart tissue is
functioning. In operation, a contrast agent is injected into the
body. When the contrast agent has saturated the myocardium of the
heart, for example, the ultrasound image of the myocardium appears
very bright. At this time, a powerful ultrasonic pulse bursts the
bubbles of which the contrast agent is comprised, causing the
myocardium to appear dark. Now, as the heart continues to pump,
contrast agent gradually fills the myocardium again. The speed with
which this occurs can be plotted, producing a time-intensity curve.
An individual TIC curve shows increasing intensity as a function of
time. The rapidity with which the contrast agent refills the
chamber is a measure of cardiac pathology (slow refill rate implies
unhealthy heart muscle). Similar quantification of blood flow can
also be done in the kidney or other perfused organs.
[0091] Several mathematical models for a TIC curve are available.
One mathematical model for a TIC curve is: A(1-e (-bt))+C [0092]
where: [0093] A, b, and C are constants [0094] t is time [0095] e
is 2.7182818. . . [0096] is exponentiation
[0097] Another commonly-used function is A*t*e (-alpha*t) +C. Both
functions are discussed in Wei et al, "Basis for Detection of
Stenosis Using Venous Administration of Microbubbles during
Myocardial Contrast Echocardiography: Bolus or Continuous
Infusion," Am Coll Cardiol 32:252-60 (1998), which is hereby
incorporated by reference. There are also measured parameters such
as arrival time, time to peak, half-time of wash-in, and half-time
of wash-out that can be used to describe the time-intensity
curve.
[0098] The mathematical model "A(1-e (-bt) )+C" is an idealization
expressing asymptotic increase of intensity from a minimum of C to
a maximum of A+C. Given a TIC curve based on real ultrasound data,
one can fit the above mathematical model, estimating the best-fit
values for A, b, and C. A, b and the product A* b have
physiological meaning and have been proposed as diagnostic of
disease. See Linka et al., "Assessment of Transmural Distribution
of Myocardial Perfusion with Contrast Echocardiography,"
Circulation 98:1912-1920 (1998), which is hereby incorporated by
reference. The following discussion of displaying b values can
equally be applied to the other parameters or their combination.
The parameter "b," which is a measure of the rapidity of contrast
agent refilling the chamber, has an average value to be found among
a population of healthy hearts, and a standard deviation about that
average value which might be found in a large population of healthy
hearts. But, an unhealthy heart might display a value of b which
differs from normal by, say, 2.5 standard deviations.
[0099] Some conventional ultrasound machines are able to produce
and display multiple TIC curves corresponding to different
locations of the heart wall. However, with this embodiment, rather
than displaying the raw curves together, the above equation would
be fitted to each of the individual curves, obtaining for each a
value of "b." Then, the normalized b's are displayed on a single
plot. Thus, the sonographer/physician sees, at a glance, not
several curves overlying each other but rather a set of "b" values
expressed in terms of how many standard deviations "b" is from
normal. Not only is this much "cleaner" to the eye (a less busy
plot), but it may also help indicate pathology more easily. In the
case where one or two curves are particularly slow, then it may be
easy to detect pathology using the traditional plotting method,
because the slow curves stand out from the crowd. But if they are
all slow, pathology may not be as obvious. However, the display of
normalized "b's" will make the pathology obvious, because all the
normalized "b's" will lie away from the "Normal" value.
[0100] Furthermore, it may be possible to develop theoretical
models for the expected "b" for different parts of the heart
muscle. In this case, each TIC measurement at a different location
would be normalized using the expected "b" appropriate for that
location, and again, the gamut of measurements would be
simultaneously displayed in a single graphical display to determine
which parts of the heart are diseased. Comparison of the multi-site
TIC curves without such normalization could be significantly more
difficult to properly interpret.
[0101] In another embodiment, a time intensity curve is plotted on
a graph similar to that shown in FIG. 7. Specifically, a single
graph displays an ultrasound contrast time intensity curve of a
study along with three curves. The first curve represents an
expected ultrasound contrast time intensity curve, and the second
and third curves represent a statistical variation of the expected
ultrasound contrast time intensity curve.
Conclusion
[0102] While the embodiments have been described above in terms of
ultrasound images, it should be noted that these embodiments can be
used with any type of medical image. Examples of different types of
medical images that can be used with these embodiments include, but
are not limited to, images created with any of the following
imaging modalities: computed tomography (CT), magnetic resonance
imaging (MRI), computed radiography, magnetic resonance,
angioscopy, color flow Doppler, cystoscopy, diaphanography,
echocardiography, fluoresosin angiography, laparoscopy, magnetic
resonance angiography, positron emission tomography, single-photon
emission computed tomography, x-ray angiography, computed
tomography, nuclear medicine, biomagnetic imaging, culposcopy,
duplex Doppler, digital microscopy, endoscopy, fundoscopy, laser
surface scan, magnetic resonance spectroscopy, radiographic
imaging, thermography, and radio fluroscopy.
[0103] It is intended that the foregoing detailed description be
understood as an illustration of selected forms that the invention
can take and not as a definition of the invention. It is only the
following claims, including all equivalents, that are intended to
define the scope of this invention.
* * * * *
References